The majority of the world's terrestrial large carnivores have undergone substantial range contractions and many of these species are currently threatened with extinction. However, there has been little effort to fully quantify the extent of large carnivore range contractions, which hinders our ability to understand the roles and relative drivers of such trends. Here we present and analyse a newly constructed and comprehensive set of large carnivore range contraction maps. We reveal the extent to which ranges have contracted since historical times and identify regions and biomes where range contractions have been particularly large. In summary, large carnivores that have experienced the greatest range contractions include the red wolf (Canis rufus) (greater than 99%), Ethiopian wolf (Canis simensis) (99%), tiger (Panthera tigris) (95%) and lion (Panthera leo) (94%). In general, the greatest range contractions occurred in Southeastern Asia and Africa. Motivated by the ecological importance of intact large carnivore guilds, we also examined the spatial extent of intact large carnivore guilds both for the entire world and regionally. We found that intact carnivore guilds occupy just 34% of the world's land area. This compares to 96% in historic times. Spatial modelling of range contractions showed that contractions were significantly more likely in regions with high rural human population density, cattle density or cropland. Our results offer new insights into how best to prevent further range contractions for the world's largest carnivores, which will assist efforts to conserve these species and their important ecological effects.

The solution depends on something that doesn't really seem to exist.

If we are obliged to consider only areas with low human population, few livestock, and a generally positive attitude to large carnivores, then we've pushed them off the map. That's already where they live. It's the problem right now.

So important to all of this is that it's made clear to everyone, the general public most of all, that the whole idea of a species is inseparably connected to a role in an given ecological system. A species is not just the body and bits of any individual of that species, but the range of behaviors it employs in the environment it inhabits. We can't keep large carnivores out of the environment for a protracted time and expect them to be able to fulfill their ancient role when they come back, because they will no longer be the same species behaviorally.

Of course, there's also the impact the loss of those apex and secondary predators will have on the food web, with their primary prey animals' populations under less predatory stress, the consequent effect on the food they eat and its role in the ecology... too complex to predict, too many variables, and too much at stake.

The same question has been asked for decades, but we're still only half answering it. Do other animals' ecology take precedence over human groups' needed living space? If so, how would we arrive at this? Enforcement? How can a democracy achieve something like this? Wouldn't it be political suicide to uproot large numbers of people and make them leave their homes?

As far as I can see, most of the large predators in the world are essentially already doomed. They're in progressive stages of extinction right now. We'll keep their appearances in zoos, we'll maintain a genetically diverse breeding stock, and they'll live out many generations at least in a walled enclosure where they're fed carrion every day. But their role will disappear and I don't know how anyone can express any degree of certainty that their ecological role can come back.